Transforming growth factor beta (TGF-beta) is a multifunctional cytokine belonging to the transforming growth factor superfamily that includes four different isoforms (TGF-β 1 to 4, HGNC symbols TGFB1, TGFB2, TGFB3, TGFB4) and many other signaling proteins produced by all white blood cell lineages.